PISI-AFS法测定煤、煤矸石和粉煤灰中微量锗

为提高煤、煤矸石和粉煤灰中总锗的测定速度,减少有机萃取剂用量,通过优化仪器工作条件,采用混合酸消解样品、蠕动进样、屏蔽式点火等方法,研究了PISI-AFS法测定煤、煤矸石和粉煤灰中微量锗含量的准确度和精密度。结果表明,该方法检出限为0.0425μg/g,相对标准偏差RSD为1.42%,标准工作曲线的线性范围达到1~400 ng/g,锗的加标回收率为98.92%~103.79%。该法与GB/T 8207—2007中的蒸馏分离-苯芴酮分光光度法的测定值的相对误差小于5%。离子干扰试验中,该法测定值的相对误差未超过±5%,说明PISI-AFS法适用于定量测定煤、煤矸石和粉煤灰中微量锗,准确度和精密度均较高。     

ICP-OES法同时测定煤中11种微量元素

为实现煤中多种微量元素的批量快速测定,煤样经高温灰化、盐酸-氢氟酸-高氯酸三元体系溶解、盐酸提取后,使用电感耦合等离子体发射光谱(ICP-OES)同时测定煤中镓钍钒磷铜钴镍锌铅铬镉11种微量元素。在对样品分解方法、射频功率、分析谱线和积分点数合理选择的基础上,通过离峰扣背景法消除了各种光谱干扰对测定的影响,建立了采用ICP-OES同时测定煤中镓钍钒磷铜钴镍锌铅铬镉11种微量元素的实验方法。方法检出限为0.03~1.17μg/g,方法精密度(n=11)0.32%~3.19%,土壤国家标准物质的分析测定值与标准值吻合较好。与传统化学方法相比,该方法快速准确,提高了分析效率,满足煤质分析的一般要求。     

ICP-OES测定铜尾矿中的铜铅锌银

为准确快速地检测铜尾矿中的铜铅锌银,选择电感耦合等离子体原子发射光谱仪(ICP-OES)对其进行测定,对实验条件、方法检出限、精密度和加标回收率做了研究。铜尾矿样品经氢氟酸-盐酸-硝酸分解后,用ICP-OES同时测定铜铅锌银4种元素,方法的检出限为0.000 62～0.003 5μg·m L-1,精密度为0.67%～3.08%,回收率为90.0%～110.0%。     

ICP-OES法测定粉煤灰中化学元素的4种前处理方法比较

采用HNO3-HF-HClO4湿法消解法、HNO3-HF-HClO4微波消解法、钠系碱法消解法和偏硼酸锂融熔法分别处理粉煤灰标准品和某电厂粉煤灰样品,利用ICP-OES法测定各组样品中K、Na、Ca、Mg、Al、Fe、Si 7种元素的含量,对比4种前处理方法的优劣势,探讨简单、快捷、准确的测定粉煤灰中矿物质元素的前处理方法。研究表明,HNO3-HF-HClO4湿法消解法的回收率范围为101. 00%~118. 20%,标准偏差(RSD)1. 49%; HNO3-HF-HClO4微波消解法的回收率范围为103. 00%~109. 80%,标准偏差(RSD)1. 58%;钠系碱法消解法的回收率范围为102. 34%~108. 61%,标准偏差(RSD)1. 62%;偏硼酸锂融熔法的回收率范围为103. 20%~109. 30%,标准偏差(RSD)1. 68%。4种方法均具有较好的准确度和精密度,但HNO3-HF-HClO4湿法消解法测得的元素含量平均值普遍偏低。所以综合考虑,偏硼酸锂融熔法操作简单、耗时短,与湿法消解法相比,可以避免使用大量酸造成对设备腐蚀和环境污染;与钠系碱法消解法相比,可以避免对K、Na元素的电离效应和基体影响。因而,偏硼酸锂熔融法可作为测定粉煤灰矿物质元素含量较好的前处理方法。     

工业级己二酸无机杂质元素的光谱研究

建立工业级己二酸中多个无机杂质元素的快速光谱分析方法。己二酸样品经硝酸溶解后直接用电感耦合等离子体发射光谱(ICP-OES)法测定其中的Na、Mg、Al、K、Ca、V、Cr、Mn、Fe、Cu、Zn、Pb等12种无机杂质元素。通过优化仪器工作参数,选择最佳的分析波长,并以Y为内标元素消除了测定过程中的光谱干扰和基体效应。在优化的实验条件下,方法的检出限为0.56~18.20μg·L-1,各元素的加标回收率为92.96%~107.90%,RSD为0.8%~3.3%。方法可实现工业级己二酸中无机杂质元素的快速准确测定。     

偏硼酸锂熔融ICP-OES测定锶矿石标准物质中锶钡方法的探讨

研究利用偏硼酸锂熔融ICP-OES法快速测定锶矿石标准物质中锶、钡含量,选取了最佳仪器分析条件,锶、钡的检出限分别为0.45μg·g-1、0.80μg·g-1,相对标准偏差(RSD)为0.43%~1.94%,回收率在97.7%~104.6%之间。该方法样品前处理简便、快捷,测定结果准确,能够满足日常生产检验要求。     

电感耦合等离子体原子发射光谱法测定硫化胶中氧化锌含量

研究电感耦合等离子体原子发射光谱(ICP-OES)法测定硫化胶中的氧化锌含量。采用干法灰化法对硫化胶进行前处理,灰化温度为550℃,灰分经无机酸溶解后,采用ICP-OES法测定试样溶液中的锌含量。结果表明:锌含量测定标准曲线相关因数为0.99991,检出限为0.005 mg·L-1;方法的加标回收率为99.3%~107.3%,测定结果的相对标准偏差小于4%。ICP-OES法测定硫化胶中的氧化锌含量简便、快速,结果准确可靠。     

X射线荧光光谱法测定伴生放射性地质样品中钛铀钍

采用X射线荧光光谱法研究伴生放射性地质样品中钛、铀、钍元素的快速测定方法。通过自制标准样品补充并拓宽了各元素的线性范围，探讨样品粒度对测定结果的影响，并进行实际样品和标准物质验证。结果显示，样品粒度应不大于0.097 mm时，经标准物质和实际样品验证，测定结果准确可靠。方法检出限低(Ti 12.35μg/g、U 0.14μg/g、Th 0.12μg/g),准确度好，RSD均小于3%,线性范围宽，简便快速，能实现伴生放射性地质样品中钛、铀、钍元素的快速准确测定。     

ICP-OES法测定碱石灰中氢氧化钠

建立了ICP-OES法测定碱石灰中氢氧化钠的含量,通过直接测定样品中的钠元素含量,间接计算获得氢氧化钠的准确含量。样品经硝酸溶液超声溶解过滤后,直接上机分析,外标法定量。结果表明:目标物钠元素在0.051～20.0 mg/L范围内线性关系良好(r=0.999 8),对测试过程中的钠元素分析谱线进行考察,幵对方法的检出限、精密度以及加标回收率进行了试验确认。结果表明方法检出限为0.049g/kg,实际样品重复检测的相对标准偏差为4.1%,加标回收率在94.5%～102%,均满足法规要求。该方法具有前处理简单、干扰少、测定快速、结果准确等优点,可用于碱石灰中氢氧化钠的测定。     

微波消解-ICP-OES法测定汽车涂料中八大重金属元素含量的仪器工作参数选择探讨

建立微波消解-电感耦合等离子体发射光谱仪(ICP-OES)分析了汽车涂料中铅(Pb)、铬(Cr)、硒(Se)、钡(Ba)、锑(Sb)、砷(As)、镉(Cd)、汞(Hg)八大元素含量的方法,对仪器工作参数RF发射功率、等离子气的流量、辅助气流量、雾化气流量、泵速、分析谱线的进行优化。结果表明,采用推荐的仪器工作参数,各目标元素的仪器检出限为0.9～21.3μg/L,仪器相对标准偏差RSD为0.99%～3.22%。改结果说明该仪器的测试条件得到了优化,ICP-OES法能适用于汽车涂料中八大元素的快速准确测定。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.